Data transmission for protocols often requires transmitter and receiver signals to have clock and data lines synchronized. Typically, the clock should be shifted 90 degrees relative to the data transmission signals for optimum protocol performance. Having such a phase shift ensures that the data has sufficient setup time relative to the clock.
There exist techniques wherein a phase shifter can be used to determine the necessary ninety degree phase shift. One problem with such a technique is that environmental parameters (voltage, temperature, etc.) impacting the phase shifter are not identical to the environmental parameters impacting a protocol controller that uses the shifted clock signal for data transmission. Such a discrepancy in environmental parameters can result in the clock phase shift changing relative to the data.